TUESDAY, Sept. 18 (HealthDay News) -- Obese adults with excess abdominal fat and insulin resistance are more likely to develop diabetes than obese adults without these characteristics, a new study suggests.

The research was published in the Sept. 19 issue of the Journal of the American Medical Association, a theme issue on obesity.

The study included more than 700 obese people, aged 30 to 65, who did not have diabetes or cardiovascular disease at the start of the study. During an average follow-up of seven years, 11.5 percent of the participants developed diabetes, according to a journal news release.

Having excess visceral fat (fat located inside the abdominal cavity, around the internal organs) and insulin resistance was associated with an increased risk for type 2 diabetes. But obese adults with higher amounts of total body fat and subcutaneous fat (underneath the skin) did not have this increased risk, the study found.

In insulin resistance, the body does not use the insulin -- a hormone that helps regulate blood sugar -- properly.

The findings suggest that assessing fat distribution and insulin resistance in obese adults may help identify those at increased risk for developing diabetes, said Dr. James de Lemos, of the University of Texas Southwestern Medical Center in Dallas, and colleagues.

The study uncovered an association between abdominal fat and diabetes risk, but didn't prove the existence of a causal relationship.

The researchers noted that rising rates of overweight and obesity have contributed to a doubling in type 2 diabetes incidence over the past three decades.